Engines



M. V. BRAINE Feb. 26, 1963 ENGINES 2 Sheets-Sheet 1 Filed July 1; .1960

gm wQ NQ INVENTOR Michael V. Broine BY I flaw

Feb. 26, 1963 V M. v. BRAINE 3,078,832

ENGINES Filed July 1, 1960 2 Sheets-Sheet 2 INVENTOR Michael V. BroineATTORNEY United States Patent Ollice 3,078,832 Patented Feb. 26, 19633,h73,332 ENGINES Michael V. Brains, 6667 Zumirez Drive, Malibu, Calif.Filed July l, 1969, Ser. No. 49,214 8 (Ilairns. (l. flit-41.65)

This invention relates to engines and more particularly to two cycleengines.

An object of this invention is to provide a new and improved engine.

Another object is to provide a new and improved internal combustionengine which is simple in design and economical of fabrication.

Still another object is to provide an internal combustion engine of thetwo cycle type having oppositely moving pistons disposed in tubularmembers or cylinders which extend between end frames mounted on the mainshaft of the engine and having gear means for connecting the main shaftto the pistons whereby reciprocation of the pistons in the cylindersimparts rotation to the main shaft.

A further object is to provide an engine wherein the thrust forces ofoppositely moving pistons are imparted in opposite directions to themain shaft whereby the housing of the engine is not required to absorbany of the thrust forces of the pistons and consequently may beeconomical in construction and light in weight.

A still further object is to provide an internal combustion enginehaving a main shaft on which a cylinder assembly is mounted and which isprovided with a gear means connecting the pistons of the cylinders to apair of crown gears mounted on opposite ends of the shaft, the crowngears and the cylinder assembly being placed under compression by stressmeans provided on such shaft whereby oppositely acting thrust forces ofthe pistons in the cylinders are counterbalanced in the main shaft.

Additional objects and advantages of the invention will be readilyapparent from the reading of the following description of a deviceconstructed in accordance with the invention, and reference to theaccompanying drawings thereof, wherein:

FIGURE 1 is a sectional view of an engine embodying the invention;

FIGURE 2 is a sectional view taken on line 22 of FIGURE 1; and

FIGURE 3 is a perspective view of one of the end frames of the engines.

Referring now to the drawing, the two cycle internal combustion engineit), which may be of the diesel type, includes a main shaft 12. and apair of end frames 13 identical in construction in which the main shaftis rotatably mounted. Each of the end frames includes a disc plate 15having an outwardly extending hub 16. The hub has an internal annularflange 18 spaced outwardly of the disc plate which provides an annularoutwardly facing shoulder 19. A pair of roller bearing assemblies 22 and23 are mounted in the hub.

Each of the roller bearing assemblies includes an outer race 25 whoseouter peripheral surface abuts the inner cylindrical surface 26 of thehub, an inner race 28 whose inner cylindrical surface engages the outersurface of the shaft, and ball bearings 29 interposed between the innerand outer spaces and held in operative position by a cage 3%. The innerannular edge surface 32 of the outer race 25 of the ball bearingassembly 23 abuts the annular shoulder 19 provided by the internalannular flange 18 of the hub whereby the movement of the ball hearingassemblies inwardly relative to the hub and therefore to the end frameis limited.

it will be apparent that the adjacent end surfaces of the races of theball bearing assemblies .22 and 23 abut one another whereby any thrustimparted to the outer race of the inner bearing assembly 23 is alsoimparted to the inner race of the outer ball bearing assembly 22.

It will further be noted that the ball bearings 29 abut outwardly facingarcuate shoulders 34 of the outer races and are rotatably disposed inarcuate recesses 35 in the outer surfaces of the inner races of the ballbearing assemblies whereby any outward thrust imparted to the outer race25 of the inner ball bearing assembly 23 is transmitted by means of theball bearing 29 to the inner races.

The outer annular surface 36 of the inner race 28 of the outer ballbearing assembly 22 engages the annular shoulder 37 of a hub 4d of acrown gear 42 non-rotatably mounted on the main shaft 12 due to theengagement of the radially outwardly extending splines 43 of the shaftin radial longitudinal recesses of corresponding configuration providedin the internal surface of the hub of the crown gear. Outward movementof the crown gear is limited by the engagement of its outer annularsurface 45 with the inner shoulder 46 of an external flange 47 of theshaft. Thus it may be seen that any thrust or force applied to the endframe 13a is transmitted by means of the internal flange 18 thereofthrough the ball bearing assemblies to the hub of the crown gear andthence to the annular shoulder as of the main shaft.

The shaft also has an outer anular end flange 49 which is receivable inan annular recess 51 of a fly wheel 52, the fly Wheel being rigidlysecurable to the end flange 49 by any suitable means, such as the bolts53 which extend through suitable apertures of the fly wheel intothreaded bores in the end flange 59.

The main shaft extends through an aperture es of the disc plate 15 and aflexible seal 61 is disposed in the aperture of to seal between the discplate l5 and the main shaft. The seal 61 may be of any suitable type,for example substantially V-shaped, and may have a garter spring 62engaging the inner flange 63 thereof to yieldingly hold the flange 63 insealing engagement with the cylindrical surface of the shaft. The otherannular flange 66 of the seal 61 abuts the cylindrical surface definingthe aperture 6E) and may be secured thereto in any suitable manner, asby a suitable adhesive or bonding agent.

A protective annular plate d3 may extend radially outwardly from theshaft outwardly of the seal 61 to limit the flow of lubricant to theseal. The protective annular plate 68 may be secured to the shaft in anysuitable manner by means of its annular flange 6% which may be welded tothe shaft.

The hub 16 is provided with a plurality of radially outw rdly extendingstub shafts 70 which are aligned with a plurality of apertures 72 in thedisc plate 15. A gear 73 is rotatably mounted on each stub shaft bymeans of any suitable ball bearing assembly 75, which may have an innerrace .76 mounted on the stub shaft, an outer race 77 disposed in thecentral annular aperture of the gear and ball bearings 78 interposedbetween the races. The teeth of the gears 73 mesh with the teeth 81 ofthe crown gear which is rigid with the main shaft 12 whereby rotation ofthe gears 73 causes rotation of the crown gear 42 and therefore of themain shaft 12.

The end frame 131) is similar in all respects to the end frame 13a andelements of the end frame 1312 have bee provided with referencecharacters, to which the subscript b has been added, of thecorresponding elements of the end frame 13a. The main shaft 12 isprovided outwardly of the seal 61!) with a protector plate tiiib whichfunctions in the same manner as the protector plate 68. The inner race23b of the outer bearing assembly 2212 abuts the annular inner shoulderor surface 85 of the hub 36 of a crown gear 87 non-rotatably mounted onthe main shaft 12 by means of the splines 88 of the shaft received inlongitudinally extending grooves of corresponding configuration in thehub 86. The crown gears 42 and 37 are held against outward movement inopposite directions on the main shaft by a pair of lock nuts 90 and 91threaded on the reduced portion of the main shaft 12. Any suitable lockmeans 96 may be interposed between the two loci: nuts to prevent theirrotation relative to each other.

The two end frames are connected by a plurality of piston cylinders M98whose opposite ends extend into aligned pairs of apertures 72 and 72b ofthe end frame 13b. The cylinders are secured to the frames 13a and 131')by means of the connector rings 16?. which are secured to the abuttingsurfaces of the disc plates in any suitable manner, as by brazing orWelding, and whose annular flanges 163 are similarly secured to thecylinders.

It will now be apparent that due to the provision of the shaft with theflange 47 at one end of the shaft and the provision of the lock nuts and)1 on the other end thereof, the main shaft 12 may be preloaded orprestressed since the engagement of the shoulders 37 and 85 of the hubsof the crown gears 42 and 557, respectively, with the internal races 28and 23b of the hearing as semblies 22 and 22b and the engagement of theinner surfaces or shoulders of the outer races 23 and 25b of the caringassemblies 23 and 23!), respectively, places the main shaft 12 undertension therebetween so that any outwardly and equal oppositely actingoutwardly directed forces exerted on the stub shafts 79 and 76b of theend frames 13a and 131'), respectively, will be transmitted to andcounterbalanced in the main shaft 12.

A pair of pistons 116 and 11611 are slidably disposed in each pistoncylinder 19 Each of the pistons may be hollow and provided with atransverse pin 112 extending through the hub 113 on one end of a pistonrod 114. The opposite end of the piston rod is provided with the hub 116which is rotatably mounted on the outwardly mounted eccentrics-allydisposed shaft 118 of a gear '73 by means of a bearing assembly 119. Thebeari g assemblies 119 are identical in construction with the bearingassemblies 75 of the hub shafts 7t) and will therefore not be describedin further detail. The gears 73 are provided with balances or weights122 to counterbalance the weight of the shaft 118.

The pistons 11% of course have the usual piston rings 125 which sealbetween the pistons and the internal wall surfaces of the pistoncylinders. The pistons 11%!) are identical in construction to thepistons and have bee provided with the same reference numerals, to whichthe letter I) has been added, as corresponding elements of the pistons11:9.

Each of the piston cylinders has a plurality of circumfcrentiallyarranged and spaced exhaust ports which open outwardly to an exhaustmanifold 131. The exhaust manifold has branches 132 which encircle eachcylinder and which communicate with a circular main section 133 of themanifold. The exhaust manifold is provided with an outlet 134 throughwhich the exhaust gases may flow outwardly to the atmosphere eitherdirectly or through any suitable muffler. Tle manifold and its branches132. may be secured to the piston cylinders in any suitable manner, asby welding or brazing.

Each of the piston cylinders is also provided with a plurality of airinlet ports 14%, longitudinally spaced from the exhaust ports, whichopen to air manifold 141 which is similar in construction to the exhaustgas manifold having substantially annular branches 142 which encircleeach cylinder and an annular main section 143 which encircles the pistoncylinders. The air manifold 141 has a suitable inlet 14-4 through whichair under pressure may be introduced into the air manifold and thencethrough the inlet ports into the cylinders when the pistons are in theextreme outward positions as shown by the upper pistons in FIGURES l and2. In this event the air under pressure may flow in from the airmanifold and its branches through the inlet ports 14% of the cylindersto force ex haust gases through the exhaust ports 13!) into the branches132 and to the exhaust manifold.

A combustible fuel, such as oil, is introduced into each cylinder atappropriate times in the cycle of operation by means of the usualinjector means 159 which have a spray nozzle 151 opening into eachcylinder at approximately the mid-point thereof so that the fuel isinjected into each cylinder when the pistons have moved to positionsadjacent to but spaced from each other, a illustrated by the lower twopistons in FIGURE 1. The space between the pistons contains a charge ofair whereby the introduction of the fuel into the cylinder between thepistons results in the immediate combustion of the fuel due to the factthat the compressed air is at a temperature sufiiciently high to causeignition of the fuel. The injection of the fuel into each cylinder mustof course be at an appropriate time in the cycle of operation of thepistons and for this reason the fiy wheel 52 is pro vided with a gear155 which may be connected in any suitable manner to the usual starter,and to the injection system of the engine which causes each injectormeans 150 to inject fuel into its associated cylinder. When the twopistons therein have moved to their innermost positions in the cylinder,the injection of the fuel thereinto causes them to move simultaneouslyoutwardly in opposite directions to cause the gears 73 and 73b to berotated simultaneously and thus cause rotation of the main shaft 12.

The pistons 110 and 11012 of the various cylinders are so arranged sothat the injection of fuel into the cylinders is effected in a definitesequence as in the usual two cycle Diesel engine.

Each of the cylinders is provided with a plurality of metallic coolingvanes 16% which extend radially outwardly from the cylinder to conductheat therefrom.

An end bell 162 is connected to the disc plate 15 of the end frame 13aby means of its radially outwardly extending annular flange 164 whichengages the outer surface of an outer annular portion of the disc plateand is rigidly secured thereto in any suitable manner, as by welding orbrazing. The end bell 162 extends around the hub of the end frame andits associated gears and may have inwardly extending strengthening ribs165. The end bell is provided with an annular flange 166 through whichthe main shaft extends. An annular seal 168 is interposed between theflange and the main shaft, between the flanges 47 and thereof, to sealtherebetween. The seal 168 may be of any suitable type.

The engine and the end bell 162 may be secured to any supportingstructure on which the engine is to be mounted by means of an attachingbracket 170 whose inwardly extending flange 17ft abuts the annular endportion 172 of the end bell 162 and is rigidly secured thereto by anysuitable manner, as by welding or brazing. The attaching bracket is alsoprovided with an external annular flange 174 having a reinforcing ring3.75 rigidly secured thereto, as by welding. The outer flange and thereinforcing ring have aligned apertures through which bolts or othermeans may extend to secure the attaching bracket to the supportingstructure.

The end bell may be provided with an inlet through which lubricatingfluids such as oil, may be injected or sprayed into the end bell andwith an outlet means duct 132 through which the lubricating fluid iswithdrawn for recirculation. It will be apparent that the lubricatingoil is sprayed over the gears and over the various bearing assemblies.The lubricating oil also splashes or is directed into the pistoncylinders behind and into the pistons themselves since the hollowpistons open outwardly into the end bell. The hub 16 is provided withports 135 througfih which the lubricating oil may fiow to the inner ballbearing assembly 23 and the disc plate as well as to the seal 61. Itwill be noted that the fluid pressure within the crankcase between theflanges 63 and 66 of the seal tends to expand the seal into tighterengagement with the shaft and with the disc plate. The seal 163 is ofsimilar construction and similarly seals between the shaft and end bell.

An end bell 195 is connected to the disc plate b of the end frame 131)by an outwardly extending annular flange 196 which abuts the outersurface of the outer portions of the disc plate 15b and is rigidlysecured thereto in any suitable manner, as by welding or brazing. Theend bell is provided at its inner edge with a flange 198 so that a seal19% may be positioned therein to engage the shaft outwardly of the locknuts 190 and 191 and seal between the end bell and the main shaft. Areinforcing ring 20f} may be rigidly secured to the end bell about theflange 198 in any suitable manner, as by welding. The end bell 195 alsois provided with inwardly extending reinforcing ribs 2tl2. The end bell195 may have a lubricating oil injecting means 204 and an outlet conduit2&5 whereby lubricating fluid, such as oil, may be caused to circulatethrough the end bell and over the moving parts of the gears, and ballbearing assemblies and the pistons.

A squirrel cage blower 210 is rigidly mounted on the main shaft 12 andhas hubs 211 and 212 non-rotatably secured to the shaft by means of thetongues 213 which are disposed in aligned recesses or grooves in thehubs and in the main shaft. The hubs of the squirrel cage blower areprovided with inlet ports 214 whereby, when the blower is rota-ting, airis pulled inwardly between the cylinders adjacent the end frames andthrough the inlet ports into the interior of the squirrel cage blowerand is then forced outwardly through the longitudinal apertures or slots2.18 thereof and between and outwardly between the piston cylinders.This circulation of the air causes air to move over the cooling vanes ofthe piston cylinders and thus provides for proper cooling of the pistoncylinders.

In use, either end of the shaft 17. of the engine may be connected to aload. The support bracket 170 is attached by bolts or other suitableconnecting means which extend through the apertures in the reinforcingring 175 and the outer external flange 174 of the bracket, to asupporting structure. The operation of the engine is initiated in theusual manner through an auxiliary starting device or by means ofstarting spark plugs which provide the means for igniting the mixture offuel and air compressed between the pairs of pistons in the cylinders.Once the diesel engine is operating, the air compressed between thepistons is so hot that the fuel will ignite immediately upon beinginjected through the spray nozzles 151 into the cylinders. The pistonsof the different cylinders operate sequentially so that when one pair ofpistons in one cylinder are approaching one another, another pair ofpistons in another cylinder are moving away from each other so that thethrusts imparted by the pistons of the different cylinders to the mainshaft occur in properly timed sequence to maintain rotation of the mainshaft and so that power is applied to the main shaft at all times.

\Vhen the fuel is injected between the pair of pistons which have movedinwardly to the extreme inward positions, as shown by the lower pistonsin FIGURE 1, the fuel is injected into the cylinder between the pistonsand its ignition creates a force which moves the pistons outwardly. Whenthe pistons 119 and 11451) move outwardly, they impart rotationalmovement to the gears 73 and 73b respectively by means of the pistonrcds 114 and 11412. If the gear 73 connected to the piston 11% of acylinder rotates in one direction, say counterclockwise, then the gear73b connected to the piston 11% of the same cylinder is caused to rotatein the opposite clockwise direction. As a result, the rotation of thegears 73 and 73b causes the crown gears 42 and $7 to rotatesimultaneously in the same direction, and since the crown gears arerigid with the main shaft, the main shaft is also caused to rotate.

When the pistons lit) and 11Gb move outwardly of the exhaust and inletports 13d and 14%? to the positions shown by the upper pistons shown inFIGURE 1, air under pressure flows inwardly from the inlet manifoldthrough the inlet ports 140 to exhaust or scavenge the products ofcombustion or exhaust gases from the cylinder and to replace them withfresh oxygen bearing air, the exhaust gases flowing outwardly throughthe exhaust ports 13%} into the exhaust manifold and thence to theatmosphere. When the exhaust gases have been scavenged, continuedrotation of the main shaft causes the pistons lit) and littb to movefrom their extreme outward positions inwardly to their extreme inwardpositions compressing the oxygen bearing air therebetween until theyagain assume their extreme inward positions. At this time a charge offuel is again sprayed into the cylinder whereupon the combustion of thefuel again imparts outward forces to the pistons.

The outward thrusts or forces imparted to the stub shafts 7t and 7% ofthe end frames 13a and 13b upon the ignition of the fuel in eachcylinder act in opposite outward longitudinal directions relative to themain shaft and such thrusts are transmitted through the internal flangesl8 and 13b of the hubs, of the end rames, the ball bearing assembliesand the hubs of the crown gears to the thrust flanges 47 and the locknuts 99 and 91 of the shaft whereby the shaft absorbs such thrusts orforces which thus counterbalance each other in the shaft since thethrust acting on the thrust flange 47 due to the movement of one pistonof a given cylinder is always opposite to the thrust imparted to theother end of the shaft by the piston of such cylinder through the locknuts 9%) and 91. Since the thrust forces of the oppositely movingpistons are absorbed and counterbalanced in the preloaded or prestressedshaft, the support bracket and the end bells may be made of lightmaterial since they do not need to absorb such thrusts or forces thusresulting in economy of construc-' tion and maintenance of the engineand also permitting light-weight construction thereof.

It will now be seen that the engine is simple in design being formed ofa pair of end frames in which the main shaft is rotatably mounted andwhich support the piston cylinders.

It will further be seen that the oppositely moving pistons of eachcylinder are connected by suitable gear means mounted on the end framesand on the main shaft to the main shaft to impart rotary movement to themain shaft whenever the pistons are moved outwardly in oppositedirections in the piston cylinders.

It will further be seen that the shaft is pro-stressed by means of thethrust flange 47 and the lock nuts and 91 to cause the crown gears ofthe shaft and the end frames to be urged toward each omer whereby thesimultaneously produced and oppositely acting thrust forces of theoutwardly and oppositely movmg pairs of pistons of the cylinders, whichare not converted to rotary movement of the gears 73 and 73b, aretransmitted to opposite ends of the shaft to act thereon in oppositedirections whereby they are counterbalanced in the shaft and need not beabsorbed by the mounting means of the engine.

It will further be noted that these thrust forces are counterbalancedsince the equal forces at all times act on the pistons of each cylinder.

It is believed obvious that, if desired, a suitable driving gear (notshown) may be mounted on either end of the shaft 12 for the purpose ofdriving a fuel injection pump, a governor, a supercharger assembly, anauxiliary generator for battery charging, or an air compressor or othersimilar device for brake control in case the engine is used for roadtransport or similar purposes. In such event, the gear might beconnected by means of the bolts 53 to the fly wheel 52 or by suitablemeans to the opposite end of the shaft 12;.

It will further be seen that while the engine embodying the inventionhas been described in connection with its operation as 21 Diesel enginewherein ignition of the fuel occurs due to the elevated temperaturepresent in the cylinder, it may operate as an internal combustion enginewherein the mixture is igni ed by a spark produced by a spark plug.

.t will further be seen that the engine could also be caused to operateas a steam engine if steam under pres sure were introduced into eachcylinder whenever the pistons thereof moved to their innermost positionsin each cylinder.

It will further be seen that the provision of an engine having spacedpiston cylinders arranged circumferentially about the shaft permits theuse of a squirrel cage blower for moving cooling air past the cylindersto maintain the temperature of the engine at a desired value.

It will further be seen that a new and improved engine has beenillustrated and described which is formed of a minimum number of partswhich are easily and quickly assemblicd.

The foregoing description of the invention is explanatory only, andchanges in the details of the construction illustrated may be made bythose skilled in the art, within the scope of the appended claims,without departing from the spirit of the invention.

What is claimed and desired to be secured by Letters Patent is:

1. An engine including: a pair of spaced end frames having aligned mainshaft apertures and a plurality of peripherally spaced aligned cylinderapertures; a main shaft extending through said main shaft aperture; aplurality of piston cylinders secured between said end frames andopening through said cylinder apertures outwardly of said end frames; apair of oppositely moving pistons in each cylinder; gears mounted onsaid end frames, said pistons being connected to said gears on said endframes; gears on opposite ends of said main shaft in meshing relationwith said gears mounted on said end frames; and means on said main shaftfor exerting a force urging said end frames toward one another wherebyoppositely acting thrust forces of the pairs of pistons in the cylindersare counterbalanced in the main shaft.

2. An engine including: a. pair of spaced end frames having aligned mainshaft apertures and a plurality of eripherallyspaced aligned cylinderapertures; a main shaft extending through said main shaft aperture; aplurality of piston cylinders secured between said end frames andopening through said cylinder apertures outwardly of said end frames; apair of oppositely moving pistons in each cylinder, said end frameshaving radially outwardly extending shafts; gears mounted on saidshafts; means connecting said gears to said pistons whereby reciprocatory movement of said pistons in said cylinders imparts rotationalmovement to said gears on said end frame shafts; gear meanslongitudinally spaced on said main shaft in meshing relation with saidgears of said shafts of said end frames; and eans on said shaft forprestressing said gear means and said end frames toward one anotaerwhereby oppositely acting thrust forces of each pair of pistons in acylinder are counterbalanced in the min shaft.

3. An engine including: a pair of spaced end frames having aligned mainshaft apertures and a plurality of peripherally spaced aligned cylinderapertures; a main shaft extending through said main shaft aperture; aplurality of peripherally spaced piston cylinders secured between saidend frames and opening through said cylinder apertures outwardly of saidend frames; a pair of oppositely moving pistons in each cylinder; gearsmounted on said end frames, said pistons being connected to said gearson said end frames; gears on opposite ends of said main shaft in meshingrelation with said gears mounted on said end frames; means on said mainshaft for exerting a force urging said end frames toward one anotherwhereby oppositely acting thrust forces of the pairs of pistons in the 6cylinders are counterbalanced in the main shaft; and blower meansrigidly mounted on said shaft between said end frames for circulatingair about and between said piston cylinders.

4. An engine including: a pair of spaced end frames having aligned mainshaft apertures and a plurality of peripherally spaced aligned cylinderapertures; a main shaft extending through said main shaft apertures; aplurality of peripherally spaced piston cylinders secured between saidend frames and opening through said cylinder apertures outwardly of saidend frames; a pair of oppositely moving pistons in each cylinder, saidend frames having radially outwardly extending shafts; gears mounted onsaid shafts; means connecting said gears to said pistons wherebyreciprocatory movement of said pistons in said cylinders impartsrotational movement to said gears on said end frame shafts; gear meanslongitudinally spaced on said main shaft in meshing relation with saidgears of said shafts of said end frames; blower means rigidly mounted onsaid shaft between said end frames and radially inwardly of said pistonfor circulating air about and between said piston cylinders; and meanson said shaft for prestressing said gear means and said end framestoward one another whereby oppositely acting thrust forces of each pairof pistons in a cylinder are counterbalanced in the main shaft, saidpiston cylinders being provided with heat exchanger means disposed inthe path of flow of air circulated by said blower means.

5. An engine including; a pair of spaced end frames having aligned mainshaft apertures and a plurality of peripherally spaced aligned cylinderapertures; a main shaft extending through said main shaft apertures; aplurality of peripherally spaced piston cylinders secured between saidend frames and opening through said cylinder apertures outwardly of saidend frames; :1 pair of oppositely moving pistons in each cylinder, saidend frames having radially outwardly extending shafts; gears mounted onsaid shafts; means connecting said gears to said pistons wherebyreciprocatory movement of said pistons in said cylinders impartsrotational movement to said gears on said end frame shafts; gear meanslongitudinally spaced on said main shaft in meshing relation with saidgears of said shafts of said end frames; blower means rigidly mounted onsaid shaft between said end frames and radially inwardly of said pistoncylinders for circulating air about and between said piston cylinders;means on said shaft for prestressing said gear means and said end framestoward one another whereby oppositely acting thrust forces of each pairof pistons in a cylinder are counterbalanced in the main shaft, saidpiston cylinders being provided with heat exchanger means disposed inthe path of flow of air circulated by said blower means; and frictionreducing bearing means interposed between said shaft and said end framesand between said end frames and said main shaft, said bearing means,said end frames and said main shaft having coengageable means fortransferring outwardly directed thrust forces exerted on the end framesto the main shaft.

6. An engine including: a pair of spaced end frames having aligned mainshaft apertures and a plurality of peripher lly spaced aligned cylinderapertures; 21 main shaft extending through said main shaft a ertures; aplurality of piston cylinders secured between said end frames andopening through said cylinder apertures outwardly of said end frames; apair of oppositely moving pistons in each cylinder; gears mounted onsaid end frames; said pistons being connected to said gear on said endframes; gears on opposite ends of said main shaft in meshing relationwith said gears mounted on said end frames; means on said main shaft forexerting a force urging said end frames toward one another wherebyoppositely acting thrust forces of the pairs of pistons in the cylindersare counterbalanced in the main shaft; friction reducing bearing meansinterposed between said shaft and said end frames and between said endframes and said main shaft, said bearing means, said end frames and saidmain shaft having coengageable means for transferring outwardly directedthrust forces exerted on the end frames to the main shaft.

7. An engine including: a pair of spaced end frames having aligned mainshaft apertures and a plurality of peripherally spaced aligned cylinderapertures; a main shaft extending through said main shaft apertures; aplurality of piston cylinders secured between said end frames andopening through said cylinder apertures outwardly of said end frames; apair of oppositely moving pistons in each cylinder, said end frameshaving radially outwardly extending shafts; gears mounted on saidshafts; means connecting said gears ,to said pistons wherebyreciprocatory movement of said pistons in said cylinders impartsrotational movement to said gears on said end frame shafts; gear meanslongitudinally spaced on said main shaft in meshing relation with saidgears of said shafts of said end frames; and means on said shaft forprestressing said gear means and said end frames toward one anotherwhereby oppositely acting thrust forces of each pair of pistons in a.cylinder are counterbalanced in the main shaft.

8. An engine including: a pair of spaced end frames having aligned mainshaft apertures and a plurality of peripherally spaced aligned cylinderapertures; a main shaft extending through said main shaft apertures; aplurality of piston cylinders secured between said end frames andopening through said cylinder apertures outwardly of said end frames; apair of oppositely moving pistons in each cylinder, said end frameshaving radially outwardly extending shafts; gears mounted on saidshafts; means connecting said gears to said pistons wherebyreciprocatory movement of said pistons in said cylinders impartsrotational movement to said gears on said end frame shafts; gear meanslongitudinally spaced on said main shaft in meshing relation with saidgears of said shafts of said end frames; means on said shaft forprestressing said gear means and said end frames toward one anotherwhereby oppositely acting thrust forces of each pair of pistons in acylinder are counterbalanced in the main shaft; and means connected tosaid end frames and extending outward in opposite directions to enclosesaid gears and said gear means.

References (Iited in the file of this patent UNITED STATES PATENTS1,324,520 Robbins Dec. 9, 1919 1,869,440 Schlenk-er Aug. 2, 19321,987,194 Gray Oct. 23, 1934- 2,099,983 Lake Nov. 23, 1937 FOREIGNPATENTS 290,048 Italy Nov. 6, 1931

5. AN ENGINE INCLUDING; A PAIR OF SPACED END FRAMES HAVING ALIGNED MAIN SHAFT APERTURES AND A PLURALITY OF PERIPHERALLY SPACED ALIGNED CYLINDER APERTURES; A MAIN SHAFT EXTENDING THROUGH SAID MAIN SHAFT APERTURES; A PLURALITY OF PERIPHERALLY SPACED PISTON CYLINDERS SECURED BETWEEN SAID END FRAMES AND OPENING THROUGH SAID CYLINDER APERTURES OUTWARDLY OF SAID END FRAMES; A PAIR OF OPPOSITELY MOVING PISTONS IN EACH CYLINDER, SAID END FRAMES HAVING RADIALLY OUTWARDLY EXTENDING SHAFTS; GEARS MOUNTED ON SAID SHAFTS; MEANS CONNECTING SAID GEARS TO SAID PISTONS WHEREBY RECIPROCATORY MOVEMENT OF SAID PISTONS IN SAID CYLINDERS IMPARTS ROTATIONAL MOVEMENT TO SAID GEARS ON SAID END FRAME SHAFTS; GEAR MEANS LONGITUDINALLY SPACED ON SAID MAIN SHAFT IN MESHING RELATION WITH SAID GEARS OF SAID SHAFTS OF SAID END FRAMES; BLOWER MEANS RIGIDLY MOUNTED ON SAID SHAFT BETWEEN SAID END FRAMES AND RADIALLY INWARDLY OF SAID PISTON CYLINDERS FOR CIRCULATING AIR ABOUT AND BETWEEN SAID PISTON CYLINDERS; MEANS ON SAID SHAFT FOR PRESTRESSING SAID GEAR MEANS AND SAID END FRAMES TOWARD ONE ANOTHER WHEREBY OPPOSITELY ACTING THRUST FORCES OF EACH PAIR OF PISTONS IN A CYLINDER ARE COUNTERBALANCED IN THE MAIN SHAFT, SAID PISTON CYLINDERS BEING PROVIDED WITH HEAT EXCHANGER MEANS DISPOSED IN THE PATH OF FLOW OF AIR CIRCULATED BY SAID BLOWER MEANS; AND FRICTION REDUCING BEARING MEANS INTERPOSED BETWEEN SAID SHAFT AND SAID END FRAMES AND BETWEEN SAID END FRAMES AND SAID MAIN SHAFT, SAID BEARING MEANS, SAID END FRAMES AND SAID MAIN SHAFT HAVING COENGAGEABLE MEANS FOR TRANSFERRING OUTWARDLY DIRECTED THRUST FORCES EXERTED ON THE END FRAMES TO THE MAIN SHAFT. 